Barracuda Project B3 Gets Stiffened for Safety and Consistency

1/22Project B3 gets stiffened up with the addition of subframe connectors and torque boxes. Additional benefits for our bracket car will be safety and consistency.

Chrysler's engineering department has always been known for designs that were well ahead of their time. Good examples of this are the Hemi engine, long ram induction, and also building cars using the "unitbody" method of construction. In fact, Chrysler was one of the first companies to build their cars utilizing this method, which uses the body, roof, and floors of the car, instead of a separate frame, to form the vehicle's structure. This method of building cars not only saves weight, but also saves time and material during the manufacturing process, thereby saving the company money. Attesting to Chrysler's foresight is the fact that nearly all modern cars, and some light trucks, are built utilizing the unitbody construction method. While this method of building cars makes good economic sense for a manufacturer, there are some drawbacks in the form of performance. Unitbody cars aren't as rigid as their framed counterparts, and the additional flex can create problems in handling, braking, and acceleration. Whether you're building a street car, or in our case a race car, there are many benefits to stiffening the car's suspension.

Body flex in a car can be both good and bad depending on what the car is used for. On one hand, less rigidity in a street cruiser does offer better ride quality-the body of the car flexes, helping to cushion the bumps of the road from the car's occupants. For a performance application, however, body flex is nearly always counterproductive. A street performance car needs to be nimble and to respond quickly to driver input so a more rigid frame and suspension are required. Limiting body flex in a race car is even more important. Today's large cubic-inch, high-powered engines simply apply more force to a car than a unitbody can safely handle. Wrinkled rocker panels, cracked windshields, and broken floor pans and frame-to-floor welds can all be the result of a high-powered engine in an unmodified factory car.

Since our Barracuda is destined for a life of bracket racing and will have a healthy big-block for power, we deemed it necessary to stiffen the suspension by adding subframe connectors and torque boxes.

Torque boxes were installed in many factory Mopars as a way to stiffen the forward leaf spring support area of the frame. Of course, all Hemi and convertible models were equipped with torque boxes, but we've also seen them installed on other cars, such as big-block-equipped A-bodies. Since most of us aren't building original Hemi cars or convertibles, chances are our cars don't have the factory torque boxes and can benefit from having them installed.

Our base model Barracuda is no exception. Since this car didn't have the boxes installed from the factory we called the Paddock and had a set of aftermarket torque boxes delivered. These torque boxes resemble, though aren't identical, to the factory units, but when installed it's hard to tell the difference. They do, however, brace the forward leaf spring mount exactly like the originals. An added benefit in our application is the torque boxes are located under where the main hoop of the rollcage will go, increasing safety by preventing the rollbar from punching through the floor in the case of a rollover accident. Installing the torque boxes is a breeze. Our torque boxes fit well with minimum amount of trimming required before welding the units in place. A welder, clamps, and metal grinder were the only tools we needed to complete the installation.

Subframe connectors were never installed from the factory, but are probably the best investment you can make in your car to decrease body flex and add rigidity. The floors in most Mopars are actually part of the car's structure, linking the front and rear subframes together. This theory works well as the floors are certainly strong enough for the average passenger car, but adding an engine with tons of torque will tax the sheetmetal floors beyond their intended limits. Floors that are rusty or have been repaired may not have the integrity of new factory floors, which only adds to the problem. Adding a framemember to connect the front and rear framerails is basically like converting your unitbody car to a fully framed car. The steel tubing doesn't replace, but rather works with the floor structure of the car to add rigidity to the vehicle. An added benefit-and this is a worse-case-scenario-is in the case of a collision from the bottom of the car (car rolls on its side and is hit by another car or hits the wall) the frame connectors have significantly more strength to resist an impact. We hope we never have to test this, but it does add significantly to the safety of our race car. Safety aside, the most noticeable benefit of stiffening our bracket car will be shown in our timeslips. A car with a stiff frame will react quicker and more consistently than a car that flexes, giving us the ability to fine-tune reaction times and accurately predict elapsed times, both very necessary components of bracket racing.

Our research of frame connectors led us to one of the leading providers of frame and chassis components: CompetitionEngineering. We chose their premade, bolt-in frame connectors because of their close tolerances and good fit. Bolt-in frame connectors are a good choice in a street car or a valuable original car as they can be removed easily to give the car its original appearance. Since our car is a dedicated race car, we'll be welding them permanently in place for even more rigidity. The bolt-in units fully encompass the rear framerails of the car and give plenty of area to weld, adding significant structural integrity to our car. Like the torque boxes, the only tools we needed were a welder, grinder, and clamps. The subframe connectors took a couple of hours to install, and other than welding, no special skills were required. If you don't have a welder or want to be able to remove the connectors, you'll need to drill holes in the car's existing frame to bolt them in. Either way the installation is fairly simple and will greatly improve the rigidity of your car. All things considered, subframe connectors are probably the best and most economic way to stiffen your car's structure.